PRD 132: Porcelain Fused to Metal Restorations

847-016 bur

In PFM, we create a Shoulder margin with __

Shoulder chamfer

In PFM, there is a __ blend

Esthetic

In PFM, we have an ___ bevel

1%

Metal ceramic represent ___ of our crowns at pacific

cast metal

Metal ceramic restorations combine the strength and accuracy of __ with the esthetics of porcelain.

porcelain

Metal ceramic restorations combine the strength and accuracy of cast metal with the esthetics of __.

reliable

PFM is considered as __ restorations

cast metal

PFM consists of a __substructure

Veneered

covered with a thin coating of a fine material

veneered

PFM has Porcelain __ for esthetics

(veneer coverage can vary)

Aggressive

PFMs have __ preparation to mask metal

substructure

Metal substrate

__ looks brighter in radiograph than the overlying porcelain

Layered Zirconia (Bilithic)

PFM have Similar radiographic appearance to__

Zirconia

__ is radiographically as bright as other metal alloys

Long span fixed partial dentures

__ indications are used (due to strength at the connectors)

Structural

PFM has more __ strength than zirconia so the joining in long span don't break

survey crown

Abutment teeth for removable partial dentures indications (2nd year)

Survey crown

- a crown which is fabricated for use as an abutment tooth for a RPD

- guide planes are formed on the axial surfaces and should be no more than 2-3 mm in occlusal gingival height

periodontal disease

A major contraindication for PFM are patients with untreated __

large pulp

A major contraindication for PFM are young patients with __ chambers because prep is really aggressive

Secondary dentin

Dentin that forms after eruption and continues at a very slow rate throughout the life of the tooth (decreases size of pulp chamber

nickel and beryllium

A major contraindication for PFM is Bio-incompatibility: Some patients are allergic to certain metals such as __

Metal alloy

Black

Opaque ceramic layer

Blue

Feldspathic ceramic

this type of silicate ceramic are the most esthetic and transulcent materials, used for veneers, can be leucite or porcelain, but have low mechanical strength (red)

Metal coping

the innermost layer of the crown, onto which the ceramic will be fused

0.3-0.5mm

What is the width of metal coping

Opaquer

conceals the metal and develops bond between metal and porcelain

Body, incisal porcelain

for esthetics, together 0.8-1mm thick for an overall required thickness of 1.1-1.5mm on porcelain veneered surfaces

Prepared tooth

Black

Metal coping

Blue

Opaquer

Red

Body porcelain

This porcelain is placed and fired on the opaque layer. It provides some translucency and contains oxides that aid in shade matching (DENTIN, YELLOW)

Incisal porcelain

-This type of porcelain is more translucent than the above types. (ENAMEL, GREEN)

Metal porcelain

No function on the __ junction

1.5 mm

Metal ceramic interface must be

ideally at least __ from all

centric occlusal contacts.

Porcelain

__ is stacked by hand (labor intensive)

surface glaze

The __ during an additional firing.

underlying body and opaque porcelain.

The perceived color of the restoration is significantly influenced by the color of the __

Gold, palladium, platinum

Noble metal casting alloys

Gold ***

Good corrosion resistance due to inherent nobility

Platinum

Increase melting point (which one?)

Nickel, cobalt, chromium, titanium

Base metal casting alloys

Principal elements

Nickel and cobalt are ___ of base metal alloys

greening

Chromium and titanium Oxidize rapidly and prevents diffusion of oxygen into underlying metal (protects it from corrosion) but these oxides could cause __ of porcelain.

Silver

Base metal may Also contain Silver, Copper and Gallium. ___ is not a noble metal (in dentistry) and could also cause greening of porcelain if present .

Oxide layer

__ that has been formed during casting should be

partially removed (either by acid or airborne particle

abrasion with aluminum oxide )

Thin

We want the controlled oxide layer to be

surface irregularities

The controlled oxide layer create __ to help with mechanical bond besides chemical bond.

chemical bonding

Manufacturers incorporate small amounts of certain base

metals that form oxides to increase __ to the metal-ceramic adherence.

match

The linear coefficient of thermal expansion from the metal

and ceramic must closely __ to achieve a strong

interfacial bond.

"wetting"

__ the alloy surface by the porcelain slurry at the

firing temperature (the opaque layer)

Glass

Dental porcelains are chemically

Quartz, feldspar, other oxides

Dental porcelains include the following minerals

Tetragonal crystals

Dental porcelains are ___ dispensed in glassy matrix

below

Porcelain must have a firing temp well __ the melting range of the metal

thermal expansion

Porcelain must have a significantly high __ compatible with the metal

wax up

1) __ for metal coping

Cast

2) metal coping is

Opaque porcelain

3) __ is added on top of coping

shades

4) porcelain __ are added

contours

5) after firing, __ corrected w/ burs

polished

6) after stain, glaze and final firing metal collar on lingual _

Adhesive failure

Between different materials

Cohesive failure

Between same material

Adhesive failure

If oxide layer was not formed between metal porcelain interface

Adhesive failure

If metal is contaminated in metal porcelain interface

Adhesive failure

If porcelain is contaminated in metal porcelain interface

Cohesive failure

If there are inclusions/voids in porcelain porcelain interface

Cohesive failure

If oxide layer too thick in metal oxide metal oxide interface

Cohesive failure ***

If metal has inclusion and voids in metal metal interface (highly unlikely)

Ceramic

PFM __ occlusal

3/4 metal

PFM __ occlusal

Metal

PFM __ occlusal

1.5mm

For metal occlusal - __ occlusal reduction

2.0mm

For porcelain occlusal - __ occlusal reduction

1.5-2.0mm

For combination occlusal - __ occlusal reduction for metal and porcelain areas respectively

Disappearing metal margin

just a line of metal seeing on the cervical in PFM

Metal and porcelain

Disappearing metal margin is a combination of

Long bevel and heavy chamfer

Disappearing metal margin is created w/ __ burs

45-65 degrees***

The angle of buccal margin

Porcelain margin

the extension of ceramic material to the finish line of the preparation without visible metal substructure in the marginal area in PFM

Metal collar margin

Generally on the lingual in PFM

120 degrees

Margin design for disappearing metal margin have a __ sloped shoulder margin

posterior

Disappearing metal margin commonly used in the __ margin teeth

buccal

We are doing this type of disappearing metal margin teeth today on the __

90 degrees

Porcelain margin is __ shoulder margin

Shoulder

Porcelain margin is a 90 degree __ margin

Esthetics

We use porcelain margin when better esthetics are involved (we aren't doing this today)

Metal collar margin

Often on lingual

Porcelain

Today, the 4 PFM has a __ occlusal

Conservation of tooth structure

• Avoid weakening tooth structure

• Avoid damaging the pulp

buccal

Today, the 4 PFM has a sloped shoulder margin (__) (disappearing metal)

Rentention

Preventing the restoration from being dislodged by forces parallel to the path of insertion (or along the long axis of the tooth) (occlusal direction)

Lingual

Today, the 4 PFM has a chamfer margin on the

Resistance

Preventing the restoration from being dislodged by horizontal or oblique forces

Structural durability

Providing adequate reduction for material strength.

Marginal integrity

Providing proper finish line for close adaptation of material to minimize bacterial microleakage.

(providing seal)

Preservation of periodontium

Providing proper shape and contour to prevent plaque accumulation for optimal periodontal health

Esthetics

qualities focused on appreciation of beauty